Dead young animals- Varanus macraei

[odatriad]

Ich entschuldige mich für meinen armen Deutschen

Dieses ist meine 4. nachfolgende Gruppe Eier von meinem v.-macraei zum Sterben am Ende der Ausbrütung, der nur Tage oder der Stunden, bevor es auftaucht. Es frustriert viel! Hat jemand ähnliche Probleme mit ihren Eiern gehabt?
http://treemonitors.com/images/a44.jpg
http://treemonitors.com/images/b43.jpg
http://treemonitors.com/images/d36.jpg
http://treemonitors.com/images/f31.jpg
http://treemonitors.com/images/b44.jpg
Zwillinge!
http://treemonitors.com/images/twins2.jpg
http://treemonitors.com/images/twins1.jpg

Haben Sie einen schönen Tag,

Bob

[Ingo]

Re: Dead young animals- Varanus macraei

Dear Bob,

thats really sad.
I am not familiar with varanid incubation conditions, but I have experienced similar problems for other lizard hatchlings.
So I dare to list the four most frequent causes for the death of "ready to hatch" lizards:
1) Suboptimal condition of the mother
2) Too high humidity at the end of the incubation time.This can result in impermeable egg pores so that the increased oxygen need during hatching kills the baby. Or, alternatively, osmotic effects may increase inner egg pressure to an extent which kills the animal.
3) Wrong incubation temperatures-mainly too warm conditions.
Gonocephalus, Acanthosaura, but also Uroplatus hatchlings often fail to hatch if the eggs were incubated too warm. The babies reach hatchling state but fail to manage egg opening or die soon after that.
4) Abnornmal thickness of eggshells: If the gravid females don´t find suitable nesting sites, they may retard the eggs for quite some time and add additional layers onto the shell.
Also for some cases a lack of shell erosion under incubator conditions is discussed as a possible source of hatching failure.

Maybe -or even quite likely - all this is not new to you.
But I have difficulties in finding other potential explanations.


Best regards

Ingo

[[ggg]Editiert von Ingo am 20-10-2005 um 07:25 GMT[/ggg]]

[Lj-Bü]

Re: Dead young animals- Varanus macraei

Hm Herr Kober, diese Geschichte mit der möglicherweise fehlenden Erosion der Eischale unter Inkubatorbedingungen finde ich furchtbar interessant, gibt es dazu Arbeiten/Artikel?

Gruss

[Ingo]

Re: Dead young animals- Varanus macraei

Also häufig diskutiert wird es jedenfalls (auch hier, SuFu!) und ich meine, mich auch an ein zwei Paper zu erinnern. Ältere aber und wenn ich mich recht entsinne lediglich bezüglich Schildkröten und Panzerechseneiern...aber ich fürchte, mir fehlt derzeit die Zeit, das zusammen zu suchen.

Vielleicht springt ja Harte oder Felix hier in die Bresche.
Die haben das sicher beide rasch zur Hand-wenn mich mein Gedächtrnis nicht täuscht und es wirklich was gibt.

Gruß

Ingo




[[ggg]Editiert von Ingo am 21-10-2005 um 08:03 GMT[/ggg]]

[Nicolá Lutzmann]

Re: Dead young animals- Varanus macraei

Hoi zsamme!

Ferguson (1981): Microbial Degradation of the Alligator Eggshell.-Science, 214(4525): 1135-1137.

Lehmann (1987) Hypothetische Überlegungen zur Schlupfproblematik von künstl. inkubierten Gelegen südamerikanischer Schildkrötenarten der Familie Chelidae.-Salamandra, 23(1/2): 73-77.

Ich hoffe, dass hilf weiter!

Gruss
Nicolà

[Ingo]

Re: Dead young animals- Varanus macraei

Prima, danke,

dann hatte ich das doch richtig im Kopf.

Evtl ist auch das eine oder andere aus folgender liste noch helfend:

Thompson, MB & Speake, BK (2002)Energy and nutrient utilisation by embryonic reptiles.
Comp Biochem Physiol A Mol Integr Physiol.;133(3):529-38

Packard MJ, Packard GC, Miller JD, Jones ME, Gutzke WH.(1985)Calcium mobilization, water balance, and growth in embryos of the agamid lizard Amphibolurus barbatus.
J Exp Zool;235(3):349-57.

Phillott AD, Parmenter CJ.(2001)Influence of diminished respiratory surface area on survival of sea turtle embryos.
J Exp Zool.;289(5):317-21

Bilinski JJ, Reina RD, Spotila JR, Paladino FV.(2001) The effects of nest environment on calcium mobilization by leatherback turtle embryos (Dermochelys coriacea) during development.
Comp Biochem Physiol A Mol Integr Physiol.130(1):151-62.

Zu diesem mal hier der Abstract, da das evtl im vorliegenden Fall relevant sein könnte und zu dem passt, was ich oben gesagt habe:

We investigated the effect of sand moisture content and sand temperature on developmental success and the mobilization of calcium during development using laboratory incubated eggs (n=251) collected from leatherbacks nesting at Parque Nacional Marino Las Baulas, Costa Rica. Calcium concentrations of egg components [eggshell, yolk plus albumen (Y+A) and embryo] changed significantly through incubation for both viable and undeveloped eggs. In developed eggs, eggshell calcium content decreased 42.9% by day 60 of incubation. The Y+A calcium decreased by 20.8% until the last quarter of incubation, and then increased to 0.99% above initial Y+A calcium concentrations just prior to hatching. In undeveloped eggs, eggshell calcium content decreased by 25.7%, with the rate of decrease slowing significantly beyond day 30 of incubation. In contrast, Y+A calcium increased steadily through the 60-day incubation period. Embryos incorporated a higher proportion of calcium when incubated at a lower sand moisture content (5% H(2)O>12% H(2)O) and at lower sand temperatures (28.5 degrees C, 29.5 degrees C>31.0 degrees C). The total wet mass of freshly oviposited eggs was negatively correlated with calcium concentration per gram of eggshell (r=-0.569; P<0.001). Thus, each yolked egg, regardless of initial wet mass, had an average of 1.23 g (+/-0.43 g) of calcium per egg (Mean egg mass: 76.24+/-1.21 g). Both developmental success (24.1%) and hatching success (7.4%) of laboratory-incubated eggs were dependent to a greater extent on temperature than on moisture, with an increase in mortality as sand temperature increased. For natural nests on Playa Grande, developmental success (37.4%) and hatching success (19.8%) were similar in magnitude to the results obtained from the laboratory. The recent ENSO (El Nino Southern Oscillation) event and increased tidal activity may be responsible for the high embryonic mortality measured during the 1997-1998 nesting season.


Gruß

Ingo

[Lj-Bü]

Re: Dead young animals- Varanus macraei

Ich bedanke mich herzlich bei den Herren Kober und Lutzmann.
Die Suchfunktion zu bedienen war mir leider nicht in den Sinn gekommen, aber danke auch für diesen Tip.

Gruss

[ulibaloo]

Re: Dead young animals- Varanus macraei

hey bob
sorry to hear about this
i bet ur as sick as a parrot
isn't this the 2nd time this has happened with blue monitors to you
what does go wrong?
any ideas?